Fuse indicator



March 17,, 1942. F. c. LA MAR 2,276,785

' FUSE INDICATOR Filed Nov. 19, 1940 I INVENTOR ATTORN Patented Mar. 17, 1942 UNITED STATES PATENT OFFICE z,zvs,was

FUSE INDICATOR Frank C. La. Mar, Tucson, Ariz.

Application November 19, 1940, Serial No. 366,255

4 Claims.

-an appreciable amount of current shall have 1nserted therein safety devices to prevent an excessve fiow of current under abnormal conditions.

A common safety device is the well known fuse made of a. strip of meta] whch will m'elt upon the flow therethrough of an undesirably heavy current.

Fuses are made of many forms, amongst which the ,cartrdge fuse is a common form. The cartridge fuse may be either of the ferrule type or of the knif blade type. In either case, it is desrable to provide a. convenient and simple form of means adapted bo indicate the fact that the fusible metalhas melted wthout making it necessary to first remove the fuse from its position and to disassemble the fuse.

It is also desirable to provide a means by w.bch the cartridge can be readly removed manually from the supporting structure, and restored thereto without making it necessary to insert the oprators band between the contact clips, or in proxmty thereto, which s of course very dangerous when a current of hgh voltage is flowng in the working ircult protected by the fuse.

An obje'ct of the invention is to provide an indicator device iormed as a hollow body of indevices for interconnecting the lamp and cartridge electrically and mechanically, whereby the indicator lamp is included in shunt wth the cartfidge in the working circuit when the cartrdge is assembled therewth in said clips. The removal of the cartridge from the contact terminal c1ips can also be effected conveniehtly by means of the'integrity indicator when constructed suitably for that purpose.

An important object of the invention is to provide an integrlty indicator in which extension terminals comprising metal c1ips whch serve to interconnect the ndcator means electrically Wth the ferrules at the ends of a cartridge fuse, so that the indica/tor Will be in shunt to the fuse,

and whch a1so serve to connect the fuse puller mechanically with the cartrdge, Wi1l be=so disposed that only those parts whch contact with the fuse cartridge ends, to carry current thereto, will be exposed, and that to a minimum ex-.

tent, the rest of these, connecting members being nsulated.

A cognate object of the invention is toencase in the insulating structure of the hollow integr1ty indicator body as much as possible of the cuzrent carrying parts, so that there is substantial1y no metal exposed beyond the mutually contiguous regions of the indicator tube and the fuse, nor beyond the line of contact extendng lengthwise therebetween; and the nventlon provides also at the ends of the tube for protection of the end parts by insulating material, in order to close in the contained current carryng parts at that ragion.

A further object of the nvention is to provide an improved mears for mounting the indica/tor lamp in the tubular insulatng support and for completing the electrical connections between the indicator lamp, ts associated resistance, and the connecting prongs or exterior terminals by whch the indicator is coupled mechmcally and electrcally to the fuse cartridge.

Still another object of this invention s the provision of a means by which the integrity of the fuslble element of a fuse may be ascertained by a visual inspection without disassembling the fuse or disturbing the position therof, and which may be applied to the common forms of ferrule type fuses, or fuses ihcluding a ferrule or cap by a. simple manual opera'ton, notinvolving permanent fastenng means.

Other objects and advantages wll appear as the descrption of the particular physical embodiment seleoted to illustrate the invention progresses and the novel features will be particularly pointed out in the appended claims.

In describng the inventon in detail and the particular physical embodiment selected to illustrate the inventlon, reference Will be had to the accompanyng drawing, and the several views txereon, wherein like characters of reference designate corresponding parts. and in Which:

Figure 1 is a side elevatonal view of a ferrule type fuse and c1ips with a fuse integrity indicator of new and improved form shown in connection therewith, the fuse integrity indicator being shown in secton; Fig. 2 is an end view of the devica as shown by Fig. 1; Fig. 3 is a crosssectional view upon the plane indicated by the l ine IIL-III of Fig. 1, vewed in the directon of the arrows at the ends of the line; Fig. 4 is a perspectve view of a fibre tube prepared for use With my invention; Fig. 1:; a perspective view of a ta1on member used with my invention; Fig. 6 is a perspectve view of a p1ug holding member used with my inventon.

Referrng especlally to Fig. 1, numerals I and 2 designate the ordinary and well known metallic clips used for receving end postioning the ordinary and well known ferrule type fuse 3 bavim; the metallc end members 4 and 5. These c1ps I and 2 ore attached to a sutable base, es 6, by any suitable or appropriate manner, as by screws 1 end 8.

As is well understood, the cartridge fuse 3\ trode III and an electrode II therein separated to form a. discharge gap which upoxrthe application of the proper electrical potental provldes for a discharge between the electrodes and the lamp 9 being filled with a. rare gas, such as neon and perhaps argon end helium, un illumination is produced which may be observed through the out out portion I2 of the tube I3.

The electrode Il! is connected by electrcal conductor I4 to a talon member, or conductor clip I5, which contacts wlth the metallica ferrule 5. The electrode II is connected by the electrical conductor l6 to one end of a resistance I'I, the other end of which ls connected by an electrical conductor |8 to the metallic talon, or conductor clip I9, which is in contact with the metallic ferrule 4.

The resistance I! may be of any sultable end appropriate form but is preferably o! very hgh resistance of the order of thirty to fifty thousand ohms and is constructed, preferably, in the form of the ordinary and well known grid 1eak resistance as used in radio. It is preferred to enclose the lamp 9 within a sheld. This sheld is preferably formed of an insulating plestic or fibre such as the well known horn fibre. The tube I3 is preferably elongated end substantially as long as the cartridge fuse 3. Each end of the tube I3 is preferably formed wth 9. out away portion, or recess, es 20 and 2|.

ber, as l5 and I9. Each talon member is formed,

as best shown in Fig. 5, in that it has a right angled portion, or tongue 22, which extends wthin the tube I3 end a. neck portion 23 which just fits within a, cut away portion 2| of the tube I3. The right angle portion 22 when assembled lies right against the materlal of the tube and s formed with serrations 24 which are bent slightly downwardly, as shown in Fig'. 5, and point toward the main portion, 25 01 the talon member. These serratons 24 out into the material of the tube I3 and so assist lnkeeping the talon member I5 in place.

In order to be entirely secure it is preferred to attach each talon member to the tube by a. rivet. Both ta1on members are similarly attached. -Talon member I5 is attached by the rivet 26 whch passes through an orlfioe 21 in edge of the ferrules es 4 arid 5.

the tube I3. has a. head 28 which bears upon the outside periphery of the tube, passes throuzh an orlfice 29 in the talon I5, and s headed a.t 30. When the rivet 26 is posltioned ar 1d headed on both ends, as described, the talon member is firmly secured in place in the end of the tube.

In some situations 1t may be unnecessary to employ the rvets es 26 but whether they are employed or not, a p1ug member as 3| s driven into each end of the tube I3. This p1ug member s made of any suitable or appropriate insulating material but preferably of a hard rubber which is slightly resilient. The plug 3I is provided with a flattened tace 32 and when the plus 1s adjusted to be driven into the end of the tube I3, the flattened portion or tace 3| is posltioned parallel to the right angle end 22 01 a talon member so that when the plug Is driven into the end of the tube, even no rivet 26 is employed, the talon member is securely held in place.

Before the talon member I5 is positloned in the tube, a 1amp positioner 33 is positioned in the tube so as to position the lamp 9. This 1amp positioner extends under a talon member, es I5, so that it is thereby held securely in place and the 1amp positioner has the right angle band 34 ha.ving an oriflce 35 thereln int which the reduced tube end of the 1amp 3 is positioned thereby holding the 1amp in place. The conductors I4 and |6 are so stf! that they also cooperate to maintain one end of the larnp in place.

The order of assembly of the parts is to position the lamp 9, es shown in Fig. 1, wth the lamp holder 33 in place, as shown in Fig. 1, after the resistance I'I has been connected to the electrical conductor I6 and the electrical oonductor I8 has been attached to the resistance a.nd attached to the talon member I9 in any suitable and appropriate manner, as by soldering. Then, if a rivet is used, it Is put in positon end headed and then a. p1ug as 3| :ls drlven into the end of the tube in place, as shown in Fig. 1. The conductor I 4 is of such length that it may be soldered to talon member I5 before talon member I5 is inserted into the end of the tube. Alter it has been so soldered to ta1on member I5, the talon member I5 is put in posltion, es shown in Fig. 1, end rvet 26 put in position and headed, taking care that lamp positioner 33 has 1ts end under the talon member, and then'plug 3I is driven in, completing the assembly.

The talon members I5 and |9 have their body portions, es 25, as shown in Fig'. 5, preferably bifurcated at 38, forming talons, and each of the talons have thelr ends as 3'! and 38 bent a1most at a. right angle with the body 25 of the talon member and the talon member is of such length thai; when so formed and es positioned in the tube es shown in Fig. 1, it may be pushed down over the end of a ferrule type fuse and the parts 31 and 38 will c1asp under the lower peripheral 'I'his clasping about the ferrules 4 and 5 may be made to .take place so strongly that the fuse integrty indi cator may be used as a fuse puller, that is, it may be used to withdraw the fuse from the clips or to replace a fuse In the clips.

As the talon members I5 end I9 are made of metal and preferably a good electrical conducting metal such as brass, the discharge electrodes II) and II of the 1amp are thereby electrically connected to the current carrying parts 4 and 5 of the fuse and so to the clips I and 2 so that when the fusible metal withln the tube 3 melts the circut is formed through the lamp 9 which thereby is illuminated a.nd gves notlce visually by arrestive indicatlon due to the peculiar colorthe fuse is not intact, but has above the bend in the metal 'talons land L9" where they project into the tube Q3 ami even here the bends are protected by insulating material on the top axxd both sides and that the cui; a.way porfisim as 20 in the tube is preferaby of such depth thai: the outer face of a talon does not go to the end line of the tube so that a. foreign body appmaching the end of the tube would not be ike; 2:; to get in contact with the current carrying fica:m bndy.

The la.mp positioned 23 may be made of any suitszble or appropriate material, it is preferred 1h make t ai an insulating material such as a thimstrip of fibre.

Altwugh I have particulafly described a-paricular embadiment of my invention ami expzzinezi the principle, construction ami mode of og:emzion thereof, nevertheless, I desire to have M: umiemcood that the form seleczed is merely illustrative but does not exhaust the posslble physicsafi embudiments of the idea ci means underlyng m37 imvention.

Wha; I claim as new and desire to secure by Lattem Patent of the United States is:

i. Am indicata: tor fuses, including a casing,

a lamp within the casing, conductor clips, means tor electrically connecting sad conductor clips to said lamp, said casing having recesses formed.

ai: each end thereof, tongues formed wlth said conductor clips and projectlng into sa.id casing, said clips also formed with a ne ck portion fltting finto said recesses, riVets, one passing through each tongue and the casing and securing thetongues to the casng, insulating resilient plugs, each formed with a flat tace, one driven into ea.ch end of the casing with the flat tace abutting the saicl tongue and each conductor clip formed with a. talon tor detachably connecting the indicator to a fuse.

3. A11 indicator for fuses, includng a. casing, a

lamp within the casing, conductor clips, means fior electrically connecting sa.id conductor clps o sa.id lamp, saicl caslng having recesses formed talon fr detachably connectlng the indicator to a. fuse.

a Zamp within the casing, conductor clips, means An indicator tor fuses, including. a. casing,

a laxnp within the.casing, conductorclips, means for electrically connecting said c'opdu'ctor clips to-said lamp, said caslng having fecesses formed ai: each end thereof, tdngues formed. with said conductor clips and projecting into said casing, each tongue formed wlth s'errations on opposite edges, said clips also formed with a. neck portion fltting finto sad recesses, rivets, one passing through each tongue and the. casing and securing the tongues .o the casing. lnsulatng resilient plugs, each forme with a. 11at face, one driven into eaeh end of the casing with the.fla)t tace abuttmg the sai tongu ancl each conductor clip formed wizh a talon tor detachably connecting the indicato: to a fuse.

FRANK C. LA MAR. 

